Why is a “D Color” diamond better than an “A Color” diamond?
The short answer is that there is no such grade as an “A color” when it comes to diamonds, or a B color or even a C color. The grading system starts with the letter “D.”
When I was at the Gemological Institute of America (GIA) getting my Graduate Gemologist degree we were taught their diamond grading system. As rumor has it, back when the grading system was developed some 70 years ago, there were local jewelry stores that had what they called their “A Quality” diamonds, so to avoid confusion the GIA decided to start with the letter D and skip the ABC letters altogether.
The letter grades start with D for colorless diamonds and go down to Z for tinted diamonds. For diamonds with even more color then Z they are graded using the GIA’s fancy color grading system. These diamonds are called “Fancy Color diamonds.” The dark blue colored Hope Diamond is probably the best known fancy color diamond in the world.
